This invention relates to a boat ladder, and in particular to a collapsible boat ladder that is capable of being fully stowed within the transom of a boat hull.
As described in U.S. Pat. Nos. 2,971,601; 3,794,140; and 3,774,720 boat ladders have been devised for mounting on the outside of a boat transom to assist boaters into and out of the water. Typically, these ladder systems are equipped with some type of mechanism that permits the ladder to be folded into a more compact unit when not in use. Even when folded, however, these ladder units usually project some distance from the rear of the boat. Accordingly, the ladder can snag foreign objects or strike against docks, pilings and the like, thereby causing damage not only to the ladder system, but also to the hull of the boat.
A retractable step for use in a small pleasure craft is further disclosed by Eckmann in U.S. Pat. No. 3,584,704. The unit is mounted in the bottom portion of a boat hull and contains a vertically disposed housing which opens through the hull below the water line. A U-shaped step is retractably contained within the housing with the ring of the step projecting through the housing opening. When a swimmer wishes to enter the boat, the step is extended to provide a platform upon which the swimmer can stand and thus more easily climb into the boat. Although the single step system is very helpful to permit a swimmer to enter a relatively small boat, it provides little or no aid to a boater who wishes to climb from the boat into the water. The retractable step of the Eckmann device is also objectionable because is opens below the water line and can thus provide a means by which water can leak into the hull. Because the ring of the step projects from the hull it provides unwanted drag and can snag underwater objects as the boat moves through the water. The single step device is of little or no use when used in conjunction with larger boats. Lastly, the ladder parts are continuously exposed to moisture and thus susceptible to rapid corrosion or becoming fouled with waterborne contaminants.
U.S. Pat. Nos. 4,146,941 and 2,669,733 both describe bow ladder units which are attached to the front of a small boat to aid the boater in getting in and out of the water. These devices are generally unsightly structures that detract from the boat lines and are highly susceptible to becoming damaged or destroyed in the event the boat strikes a dock, piling or the like.